Comparative Energy Analysis Research Articles

Energy comparative analysis of power units for use in light aircraft

In reference to the research conducted on environmentally friendly sources of propulsion for aircrafts, there was carried out an energetic comparative analysis for power units using various power sources. For this analysis, the AOS-71 glider airframe was used. The calculations were done for different variants: a combustion engine, an electrical engine, a hybrid combustion engine and a hybrid engine with a hydrogen cell. The research was based on the assumption of the same aircraft take-off weight of 660 kg. The energy accumulated on board was determined, and then the duration and range for each type of propulsion for two flight trajectories. The results were present-ed in diagrams and discussed in the conclusions.

Generating electrical energy through urban solid waste in Brazil: An economic and energy comparative analysis

The search for alternative energy sources and increasing concerns over the generation of municipal solid waste are two widely discussed themes in contemporary academic literature. A possible alternative for solving both of these problems is through electrical energy generation through the use of this waste material. Although this practice is encouraged by the Brazilian National Solid Waste Policy, energy production through such methods still requires improvement. Given these considerations, this study aims to evaluate the generation of electric energy from solid waste in three different systems (biogas from sanitary landfills; methanization of organic fraction in anaerobic digesters; and combustion in incinerators) through economic and energy analysis. Economic analysis was performed with the parameters Net Present Value and Levelized Cost of Electricity. Economic viability was only seen in the cases which considered landfill biogas energy recovery, demonstrating a need for incentives and support policies to enable technologies that are environmentally more advantageous than landfills.

Comparative Energy Analysis of Photovoltaic Module

This work introduces a comparative energy analysis of photovoltaic module using its different single diode equivalent electrical circuits (five-parameter model, four-parameter model, and ideal model). These equivalent circuits are used for different purposes according to the objective. The ideal model is still used in many applications particularly power system analysis and water pumping. Three commercially available (SUNTECH) photovoltaic modules (50W, 70W and 130 W) are used in this analysis at standard test conditions. Using those three PV modules; the relative errors of the maximum output power mismatch are highlighted in the three cases. Obtained results show that the five-parameter model gives the most accurate maximum power prediction in comparison to that of manufacturer’s data sheet, while the ideal model shows a remarkable relative error at the maximum output power which is up to 8.93013%. This evaluation allows users deciding on the selection of appropriate equivalent circuit to be used in a given application.

Análisis Comparativo de Indicadores Energéticos de Países Miembros de la Comunidad Andina de Naciones

La condición simétrica de los países miembros de la CAN y sus semejanzas de mercados, permitió el cálculo de indicadores económicos energéticos para el desarrollo. Dentro del análisis se destaca la condición excedentaria de energía del bloque, la cual se ve opacada por la baja integración energética existente.
 El análisis consta de una serie histórica de datos que van desde el año 2000 hasta el 2015, basados en la información disponible obtenida de las agencias energéticas oficiales. Como resultados principales, tenemos que los Países miembros: Colombia, Ecuador y Perú tienen tendencias semejantes conformando un conglomerado, mientras que Bolivia presenta valores distantes del mismo. No obstante, después del 2010, la sociedad boliviana presenta avances progresivos en el resultado de los indicadores.
 Como conclusión general, el bloque tiene muchas oportunidades para dar avances significativos en el aspecto económico energético y llegar a altos niveles de desarrollo, definiendo estrategias comunes y fortaleciendo su integración.

Hybrid systems adoption for lowering historic buildings PFEC (primary fossil energy consumption) - A comparative energy analysis

Abstract In the last decade, the European Union promoted several directives dealing with strategies and methodologies pertaining to buildings energy demand reduction. To accomplish fixed targets, a different design philosophy has to be adopted for new buildings construction. Additionally, RES (Renewable Energy Sources) have to be integrated as much as possible and non-invasive refurbishment interventions, matching architectural constraints for existing buildings have to be considered. This work explores the possibility to apply small scale hybrid energy systems generating electricity and high temperature heat which are compatible with typical limitations of historic buildings. To do so, six different plant layouts have been implemented, combining CHP (combined heat and power), PV (photovoltaics) arrays, PV/T (solar hybrid collectors), electric heat pumps, trans-critical CO2 heat pumps and gas heat pumps. Moreover, the potential effects of hydrogen enrichment in Natural gas, on the selected plant layouts have been investigated. Thus, all of energy scenarios have been compared each other based on four different indicators such as PFEC, building EPg (Energy performance index), RES fraction and renewable heat. Finally, a sensitivity analysis with varying the building PTHR (Power To Heat Ratio) has been carried out in order to identify under what conditions each layout is the most efficient.

Thermodynamic properties and energy characteristics of water+1-propanol

By using own precise experimental data on p,ρ,T,x- relations differential and integral thermodynamic properties of water+1-propanol homogeneous binary mixtures (0.2, 0.5, and 0.8 mole fractions of 1-propanol) were obtained in one phase (liquid, vapor) region, along coexistence curve phase, at critical and supercritical regions of parameters of state. These values were obtained in the regions of temperatures 373.15 – 673.15 K, densities 3 – 820 kg/m3 and pressures up to 50 MPa. It is found that shape of p,ρ,T,- dependences of water+1-propanol mixtures in investigated range of temperatures is the same with those of pure liquid, but the pressure of the mixture is higher than those of pure water or 1-propanol. The critical line of water+1-propanol binary mixtures as opposed to those of water+methanol and water+ethanol mixtures has convex shape. It is ascertained that using water+1-propanol mixture (0.2 mol.fraction of 1-propanol) instead of pure water allows to decrease lower limit of operating temperatures to 50 K, to increase effective coefficient of efficiency and partially unify thermal mechanical equipment of power plant. Our comparative energy analysis of cycles of steam-turbine plant on water and water+1- propanol mixtures, carried out at the same thermobaric conditionsand showed that thermal coefficient of efficiencyofcycle of steam-turbine plant onwater+1-propanol mixture (0.2 mol.fraction of 1-propanol) is higher than those of pure water.Thus and so we made a conclusion about usability of water+1-propanol mixture (0.2 mole fraction of 1-propanol) as a working substance of steam-turbine plant cycle.

A comparative energy analysis of three electrochromic glazing technologies in commercial and residential buildings

This paper presents a simulation study of three dynamic electrochromic window glazings, including a novel glazing capable of independently modulating its optical properties in both the visible and near-infrared spectrums. This capability allows this so-called “dual-band” technology to actively manage the solar heat and visible light transmitted into a building’s interior, and creates the potential for heating, cooling, and lighting savings vis-à-vis competing window technologies. In this study EnergyPlus is used to simulate annual energy performance of the dual-band electrochromic (DBEC) glazing in three building types and 16 U.S. climate regions. The savings potential of DBEC windows are presented relative to a conventional electrochromic glazing; a visibly transparent, near-infrared switching electrochromic glazings; and several static alternatives, including ASHRAE 90-2010 standard compliant windows.Results indicate that the DBEC glazings are capable of outperforming alternatives in a diverse set of locations and building types, including both heating and cooling-dominated regions. Relative to code-compliant static windows, the DBEC is capable of achieving annual primary energy savings between 6 and 30kWh/ft2 of window area from reduced heating, cooling, and lighting demand. Relative to other advanced glazings, the savings are significantly lower, ranging from 0 to 1.2kWh/ft2. Regional DBEC energy cost savings versus high performance static windows are presented to identify early potential market entries based on energy savings. Finally, the impacts of widespread deployment of high-efficiency LED lighting on DBEC energy savings potentials are also presented.

Роль региональных властей в обеспечении энергетической безопасности субъектов РФ

Introduction. Energy efficiency and energy security of Russia’s regions are among the main indicators of the national economy development, showing the degree of protection of the regional population and business from internal and external threats. They also reflect the sustainability level of economic and social spheres in the regions and increasingly determine the quality of life of the population. This is important in the context of sustainable development of territories and social communities. Various energy efficiency programs are a central component of the energy policy in many countries at federal as well as regional and local levels.Aims. Based on the analysis of modern scientific approaches in the field of sustainable development, energy efficiency and improving the quality of life of people, the research was aimed at a comparative study and analysis of dynamics of energy supply and energy efficiency in Russian regions, as well as studying the role of regional authorities in ensuring the energy efficiency of the regional economy.Methods. The research method is a comparative analysis of energy and energy efficiency ratings of Russian regions for 2011–2016.Results. Comparative analysis is an effective management tool that allows to control which regions are in line with the current state policy in improving energy efficiency and how successfully they achieve their goals.Conclusion. The results of the research are of practical importance from the point of view of identifying strengths and weaknesses in the regional and municipal authorities’ activities to ensure measures aimed at improving the energy efficiency of the regional economy and housing and communal services.

Quantum-chemical study of activation of yellow phosphorus by copper(II) chloride

Catalytic properties of Cu2+ ions in oxidation reactions of P4 were investigated in present work using quantum-chemical methods. The geometric structures of several transition metal complexes were determined. The oxidation of P4 molecules in reactions with alkane hydroxide compounds by means of interaction with Cu2+ ions is substantiated based on comparative analysis of energies. The mechanism of activation of P4 molecular cations is studied. The possibility of occurrence of the reaction is shown based on thermodynamic parameters.

Energy evaluation of protection effectiveness of anti-vibration gloves

This article describes an energy method of assessing protection effectiveness of anti-vibration gloves on the human dynamic structure. The study uses dynamic models of the human and the glove specified in Standard No. ISO 10068:2012. The physical models of human–tool systems were developed by combining human physical models with a power tool model. The combined human–tool models were then transformed into mathematical models from which energy models were finally derived. Comparative energy analysis was conducted in the domain of rms powers. The energy models of the human–tool systems were solved using numerical simulation implemented in the MATLAB/Simulink environment. The simulation procedure demonstrated the effectiveness of the anti-vibration glove as a method of protecting human operators of hand-held power tools against vibration. The desirable effect is achieved by lowering the flow of energy in the human–tool system when the anti-vibration glove is employed.

Comparative energy analysis on a new regenerative Brayton cycle

Gas turbines are frequently used for power generation. Brayton cycle is the basis for gas turbine operation and developing the alternative cycles. Regenerative Brayton cycle is a developed cycle for basic Brayton cycle with higher thermal efficiency at low to moderate pressure ratios. A new regenerative Brayton cycle has been introduced in the present study. Energy analysis has been conducted on ideal cycles to compare them from the first law of thermodynamics viewpoint. Comparative analyses showed that the new regenerative Brayton cycle has higher thermal efficiency than the original one at the same pressure ratio, and also lower heat absorption and exhausted heat per unite output power. Computed results show that new cycle improves thermal efficiency from 12% to 26% relative to the original regenerative Brayton cycle in the range of studied pressure ratios. Contrary to the original regenerative Brayton cycle, regenerator remains useful in the new regenerative Brayton cycle even at higher pressure ratio.

Integrated Evaluation of Co2eq Emission and Thermal Dynamic Simulation for Different Façade Solutions for a Typical Office Building

This paper presents the results of comparative analysis of energy and environmental life cycle assessment of a building envelope with different WWR. The analysis is simplified to: product stage and use stage as the main sources of GHG emissions. Embodied and operational CO2 equivalent were evaluated for two typical office buildings located in Poland with different wall to floor ratio. Carbon footprint of the use stage, associated with the energy consumption, was calculated according to polish energy fuel mix.The maximum emission of CO2eq occurred for the scenario with glass curtain wall and it decreased along with reduced window area.

Energy Savings Potential for Pumping Water in District Heating Stations

In district heating stations, the heat carrier is circulated between the energy source and consumers by a pumping system. Fluid handling systems, such as pumping systems, are responsible for a significant portion of the total electrical energy use. Significant opportunities exist to reduce pumping energy through smart design, retrofitting, and operating practices. Most existing systems requiring flow control make use of bypass lines, throttling valves or pump speed adjustments. The most efficient of these options is pump speed control. One of the issues in using variable-speed pumping systems, however, is the total efficiency of the electric motor/pump arrangement under a given operating condition. This paper provides a comprehensive discussion about pump control in heating stations and analyzes the energy efficiency of flow control methods. Specific attention is also given to the selection of motor types, sizing and pump duty cycle. A comparative energy analysis is performed on the hot water discharge adjustment using throttling control valves and variable-speed drives in a district heating station constructed in Romania. To correlate the pumped flow rate with the heat demand and to ensure the necessary pressure using minimum energy, an automatic system has been designed. The performances of these control methods are evaluated in two practical applications. The results show that approximately 20%–50% of total pumping energy could be saved by using the optimal control method with variable-speed pumps. Additionally, some modernization solutions to reduce the environmental impact of heating stations are described.

Residential energy consumption trends, main drivers and policies in Lithuania

Abstract Environmental pressure from residential energy use is projected to significantly increase by 2030. Different environmental policy measures provide different incentives for “environmentally responsive” consumer choices and behavioural responses. There is a great energy saving potential in residential buildings of Lithuania. Compared to the other EU countries with similar climate conditions, energy consumption for residential heating is approximately 1.8 times higher in Lithuania. About 60% of Lithuanian population resides in multi-apartment buildings constructed during 1961–1990. The aim of the paper is to define the main drivers of residential energy use in Lithuania and to compare energy saving technologies in terms of energy saving potential and costs in Lithuanian residential buildings. Seeking to achieve the aim the main tasks of the paper are to analyse theoretical issues of the main drivers of residential energy use; to analyse residential energy use trends in Lithuania and to compare these trends with other EU member states; to define the main drivers of residential energy use by applying correlation analysis; to analyse policies aiming to reduce energy consumption in residential buildings and their impacts on GHG emission reduction. The comparative study of residential energy use in Lithuania and several old EU member states showed that residential energy use per capita in Lithuania is significantly lower than in old EU member states because of the lower income per capita and lower living standards. The economic and technological factors are the main driving forces of final energy consumption in all compared EU member states; however the impact of different factors varies between countries. The comparative analysis of energy saving and GHG emission reduction potential and costs in residential buildings provided by different studies showed that the most cost-effective instruments were appliance standards, energy efficiency obligations, Demand Side Management programs, public benefit charges and labelling.

Energy and Environmental Impacts of Urban Buses and Passenger Cars–Comparative Analysis of Sensitivity to Driving Conditions

A methodology is suggested for a comparative analysis of energy and environmental impacts of various urban transport modes. A total emission indicator is used as a tool for integral assessment of vehicle emissions. An environmental impact factor is suggested in order to compare between the various transport modes that use different energy sources. Vehicle occupancy values, yielding equality of the specific environmental impact factors and specific energy consumption of the compared transport modes are used for the analysis purposes. This methodology is applied for a comparison between the buses and the passenger cars at various levels of service, road gradients and urban road types. The comparison results reveal that the environmental impact of the bus for driving at an urban access road falls below the one of the passenger car when the bus occupancy is 14–18 persons. Urban buses turn out to be energetically beneficial over passenger cars at occupancy values substantially lower compared with those providing a similar environmental impact.

Comparative analysis of energy produced by photovoltaic modules with anti-soiling coated surface in arid climates

Dust accumulation on the surface of photovoltaic modules decreases the transmittance and produces power losses and consequently daily energy losses. These losses are important in large photovoltaic power plants, mainly in arid areas. The company Asahi Kasei Corporation has developed a new self-cleaning coating for photovoltaic applications. The performance of photovoltaic modules can be increased due to the two main properties of the coating film: anti-reflectiveness and self-cleaning effect. The aim of this work is the comparative evaluation of the energy produced by photovoltaic modules with and without anti-soiling coating. For this purpose, six photovoltaic modules of the same manufacturer and technology, three with coated surface and three without it, have been tested under outdoor conditions for a year in the laboratory of photovoltaic systems at the University of Málaga, southern Spain. Our results show that dust accumulation on the surface of the module reduces the performance in terms of energy and power, due to a decrease of the transmittance. Furthermore, the non-homogeneity of the distribution of dust on the surface of the module causes additional power losses. Obtained outcomes show that in dry periods (without rainfall) energy soiling losses are much higher. In these cases the energy losses for both kinds of photovoltaic modules reach significant values, but daily energy soiling losses are greater for modules without self-cleaning coating. Modules with coating film have an average daily energy soiling losses of 2.5% whereas for the uncoated modules this value is 3.3%.

Structural characteristics of nanoparticles produced by hydrothermal pretreatment of cellulose and their applications for electrochemical hydrogen generation

Hydrothermal pretreatment (HTP) of microcrystalline cellulose (MCC) and wood sawdust in water at 200 °C and 250 °C and at pressures up to about 600 psi for different heating times (≤60 min) is shown to produce nanoparticles of about 210 nm diameter. For the shorter treatment times of 15 min, only partial conversion is observed. Investigations of the post-HTP solid products by scanning electron microscopy show that the original size of cellulose particles is reduced by a factor of about 50 to yield spherical nanoparticles of about 210 nm size. In X-ray diffraction studies, the characteristic Bragg peaks of the parent MCC and sawdust are not present in the post-HTP products with only a broad halo being observed, indicating that the crystallinity of cellulose has broken down under HTP. Electron spin resonance (ESR) spectroscopy shows the observation of free radicals in the post-HTP products whereas the parent MCC, sawdust and glucose are ESR inert. FTIR spectroscopy shows the breakdown of the bonds between glucose units of the cellulosic structure. As an application, the pre- and post-HTP cellulose and sawdust were tested for the electrochemical production of hydrogen. Whereas the pre-HTP samples were found to be inactive, the post-HTP cellulose treated at 250 °C for 60 min was nearly as active as carbon BP2000 (surface area = 1500 m2/g) for producing H2 at energy efficient voltages. A comparative energy analysis for the electrochemical production of hydrogen using carbons and post-HTP cellulose vis-a-vis water electrolysis is also presented.

Life cycle assessment of building materials: Comparative analysis of energy and environmental impacts and evaluation of the eco-efficiency improvement potential

The building industry uses great quantities of raw materials that also involve high energy consumption. Choosing materials with high content in embodied energy entails an initial high level of energy consumption in the building production stage but also determines future energy consumption in order to fulfil heating, ventilation and air conditioning demands. This paper presents the results of an LCA study comparing the most commonly used building materials with some eco-materials using three different impact categories. The aim is to deepen the knowledge of energy and environmental specifications of building materials, analysing their possibilities for improvement and providing guidelines for materials selection in the eco-design of new buildings and rehabilitation of existing buildings. The study proves that the impact of construction products can be significantly reduced by promoting the use of the best techniques available and eco-innovation in production plants, substituting the use of finite natural resources for waste generated in other production processes, preferably available locally. This would stimulate competition between manufacturers to launch more eco-efficient products and encourage the use of the Environmental Product Declarations. This paper has been developed within the framework of the “LoRe-LCA Project” co-financed by the European Commission’s Intelligent Energy for Europe Program and the “PSE CICLOPE Project” co-financed by the Spanish Ministry of Science and Technology and the European Regional Development Fund.

Street geometry and energy conservation of urban buildings in Chicago

A relationship of building space conditioning energy and density of built-up area using street geometry as an urban design parameter was investigated in this study. Sixteen street geometry configurations with varying street width and orientation were investigated. A comparative energy analysis of a single, stand-alone eight-storey office building, with the same building as a part of urban building configuration, is presented. The sensitivity of microclimatic changes of increased air temperature and reduced wind speed was investigated for the building energy need of a compact street geometry. Additionally, the role of improved wall and roof surface albedo values on energy needs was studied in the urban context. The street geometry significantly influences the space conditioning energy of an urban building. The summertime cooling load of a code rated energy efficient building is reduced by up to 37% whereas heating loads are penalized by 19% by the studied street aspect ratio of 8. However, microclimatic influences can reduce cooling energy savings by up to 8% and reduce heating energy penalty by 15% for the Chicago climate. High cooling load reduction by a high street aspect ratio is synonymous with high achievable density of the built-up area, but blocked daylight access increases the need for artificial lights. In summary, higher street aspect ratio represents a compact development and promises higher annual cooling energy savings; however, selection of environment- and development-friendly street geometry remains a compromise for energy efficient building.

Comparative analysis of energy impacts of traditional and partly electronic environmental auditing: learning from the Japanese automotive industry case

This paper does a comparative analysis and assessment of energy impacts of traditional and partly electronic ISO 14001 environmental management system auditing that using videoconferencing systems. The focus is on the Japanese automotive industry. The idea is to quantify the environmental impacts of auditing and resolve the important question on whether or not the use of information and communication technology (ICT) in environmental auditing reduces environmental impacts in ISO 14001 environmental management systems. The main results show that there are no clear energy savings or environmental advantages associated with ICT use in environmental auditing for the set system boundary. However electronic auditing is shown to have clear advantages for stated variables within the model, for example when the distance travelled by the auditors by train and by car is less than 75 km and 17 km per day respectively. A comparison of modes of travel by auditors, shows that rail travel offers the most environmental and energy benefits. It is also noted that travel dominates in terms of energy consumption and environmental burdens compared to all other environmental aspects associated with auditing. The study contributes to knowledge in that among other things, it enables researchers to draw parallels from it applicable to other industrial sectors and other countries. Southern African countries can use this methodology in analysing auditing methods with little or no changes in the model used.